"Naruto... it's too late, nothing you can say will change me! I'm going to kill you and every last person in your beloved village! It's time to make your choice! Kill me and become a hero, or die at my hand and become another one of my victims!"

Sasuke was a happy child, eager to please and be worthy of his family name. This changed after his entire family was killed by Itachi, the person he most admired in the world. He became cold toward others, unmoved by and uninterested in what they do or think of him, choosing instead to keep to himself. He stopped using honorifics like "sensei" or "sama", something considered rude in the Japanese language. His only goal in life became to take revenge for his family's deaths and, by extension, acquire the power needed for that revenge, even if it meant acquiring an external power that wasn't his own.

Otaku Trivia:

1) Sasuke's favourite foods are omusubi with okaka and tomatoes, while his least favourites are nattō and anything sweet.